FED-STD-791D
19.
Start the support oil pumps; there should be at least 414 gage kPa (60 psig) manifold
pressure. At the screw thread seal there should be at least 0.8 cm (0.3 in) of oil
positive pressure relative to the support oil side (manometer leg to test compartment
lower).
20.
Set and maintain the support oil pressure at 552 to 689 gage kPa (80 to 100 psig) by
means of a regulating valve.
Allow oil temperature at the support scavenge line to reach at 38.8C least (100F).
21.
Start the bearing drive motor; the bearing speed is preset at 10,000 rpm. (If bearing
22.
drive is not constant speed, follow motor operating instructions to bring it up to the
necessary speed.)
23.
Turn off the load by-pass switch.
Apply a load to the test bearing. Increase the load on the bearing gradually with the
24.
load controls. The load cylinder pressure should be held at 352 gage kPa (51 psig).
Continue running until the following conditions have been stabilized:
25.
121 " 2.5C
(250 " 5F)
Test oil-in temperature
138 " 2.5C
(280 " 5F)
Test tank bulk oil temperature
(0.35 " 0.05 ft3/min)
Air flow, end cover
9.9 " 1.4 L/min
(corrected)
(corrected)
Make at least two separate flow checks of one-minute duration each at the three-way
26.
valve position on the pressure side of the scavenge pump. The measured volume
flow rate should be 600 " 30 mL/min. The hot test oil collected during the flow
check should be poured immediately back into the test oil tank through the fill port
and the port recapped.
27.
Continue running for one hour at these conditions with the bearing heater off. If
during or at the end of this period, the maximum bearing temperature has exceeded
177C (350F), shut down the rig, install a new test bearing, and repeat items 1
through 26. If the maximum bearing temperature has not exceeded 177C (350F)
during this period, proceed with the next step.
28.
Turn on the test bearing heater and adjust indicator flag to the target temperature on
the temperature controller.
29.
Check the three test bearing outer-race thermocouples to make sure that the second
highest indicating thermocouple is connected to the temperature controller. Maintain
260C (500F) on the highest indicating thermocouple
30.
Adjust the test oil tank thermal switch so that the target temperature for the type of
test being run is met within 30 minutes (minimum) and 60 minutes (maximum).
Maximum heater skin temperature should not exceed 29C (85F) above test oil
target temperature during the warmup period. The nozzle temperature should be
maintained at 177 " 2.5C (350 " 5F).
Test type
1
1-1/2
2
171 " 2.5C
199 " 2.5C
227 " 2.5C
Target temperature
(340 " 5F)
(390 " 5F)
(440 " 5F)
132
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